Fastener apparatus for roofing and steel building construction

ABSTRACT

A fastener apparatus includes a frusto-hemispherical head portion having a flat top surface, a curved outer surface, a base portion, and a peripheral edge, with the flat top surface bearing a tool fitting. A downwardly-depending lip portion extends from the head peripheral edge and defines an annular recess in the base, the annular recess having a flat upper surface. The lip has a curved outer edge, a curved lower edge, and an inner edge having a curved lower portion and a vertical upper portion terminating in the annular recess flat upper surface. A shank portion is connected to the base and bears screw threads and a tip. An annular gasket portion is carried on the shank, and has a first uncompressed position contained radially within the annular recess, and a second compressed position extending radially beyond the lip outer edge. As the fastener is installed in a workpiece, the gasket expands to contact the lip inner edge and extend beneath the curved lower edge to form a seal between the fastener head and the workpiece. The fastener may include locking teeth terminating in the head base, adapted to resist loosening of the fastener from the workpiece. The curved outer surface of the fastener may include asymmetric ridges adapted to mechanically engage moving snow or ice to resist loosening of the fastener from the workpiece. The fastener head preferably has a width to height ratio of between 3:1 to 5:1.

CROSS REFERENCE TO RELATED APPLICATIONS

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

Not applicable.

TECHNICAL FIELD

The present invention relates generally to construction hardware, andmore particularly to an improved fastener apparatus for use in roofingand steel building construction.

BACKGROUND INFORMATION AND DISCUSSION OF RELATED ART

Fasteners for use in roofing and steel building construction currentlyinclude the ring shank self-sealing nail and the self-sealing hex head.Manufacturers of metal roofing panels recommend that the originalself-sealing fasteners be replaced every five years. This replacement isnecessary because the rubber seals used on the fasteners are damaged bythe sun's UV rays in five years. In addition, snow falls and lands onthe rooftop, and when the snow tries to slide off the roof it packsagainst the high profile heads of the existing screws and builds up,staying on the roof by hanging on the high profile hex head screw. Thehigh profile screw heads cause the snow and ice to build up to a greatweight before unloading, because the screw heads act like little dams,stopping the snow from unloading. Ice is caused when the heat frominside the home melts the underside of the snow load in the daytime andit then re-freezes each night. Once the weight of the snow and ice istoo much for the fasteners to support, the snow breaks free andviolently unloads from the roof. The friction caused by the ice tearingand ripping its way over the hex head screws as it unloads from the roofis exactly what destroys the fasteners. These forces are too great andthe cause is the vertical walls and high profile caused by the hex headfasteners themselves.

U.S. Pat. No. 4,701,088 to Crull discloses an undercut, sealing threadedfastener for engagement with an internally threaded workpiece, and amethod of forming the same as provided. The fastener comprises a driverhead and a shank extending axially from an undersurface of the driverhead. The shank includes an intermediate unthreaded portion and athreaded portion defining a given thread form having a crest diameterand a given root diameter. An undercut groove is provided in theundersurface of the driver head, this undercut groove having an innerdiameter no greater than the crest diameter of the internal or femalethread, and preferably also no greater than the root diameter of theexternal thread, and an outer diameter greater than the crest diameter.An unthreaded shank portion is formed intermediate the threaded shankportion and the driver head and extends continuous with the innerdiameter of the undercut groove. This unthreaded shank portion thushaving an outer diameter no greater than the internal thread crestdiameter and preferably not greater than the external thread rootdiameter. An annular sealing ring is engaged about the unthreaded shankportion and extends into the groove.

U.S. Pat. No. 5,622,464 to Dill, et al. teaches a screw for use with awasher as a sealing fastener having formations near the head of thescrew to increase driving resistance when the portion having theformations reaches a surface into which the screw is being drilled. Thescrew includes a shank with a tip end and a head end. A head at the headend may be driven by a driving tool such as a pneumatic or electricdrill. To facilitate retention of the washer the head has a flange thatforms a recess. The shank has an enlarged portion near the head adjacentto the recess and the enlarged portion has ridges. The enlarged portion,including the ridges, increases the driving resistance of the screw.This increase in resistance gives notice to an operator of the drivingtool that an appropriate driving depth and torque have been achieved.Preferably, the washer has an inner diameter surface with fully radiusedprojections. The projections assist in mounting the washer to the screwand keeping the washer appropriately positioned on the screw duringdriving of the screw.

U.S. Pat. No. 6,231,286 to Bogatz, et al., describes a headed fastenerwith a precisely calculated groove under the head to accommodate anO-ring sealing member as a self-sealing assembly for sealed engagementwith a workpiece. The fastener has a head having a lower face, and ashank extends from the lower surface of the head. A groove is formed inthe lower surface, the groove having an inner wall and an outer wall.The inner wall has a proximal end which is adjacent the lower surface ofthe head and which is disposed radially remotely from the shank. Asealing element, such as an O-ring, is disposed at least partiallywithin the groove. The groove may be configured so that a distal end ofthe inner wall is near to the axis of the shank than is the proximal endof the inner wall.

U.S. Pat. No. 6,764,262 to Hargis discloses a weatherproof fastenerhaving a shank and head, the latter formed with a recess in its lowersurface. A gasket is positioned in the recess, which it partially fillsuntil the screw is employed to joint two elements and the gasket iscompressed so that it fills the entirety of the recess, therebypreventing the ingress of undesirable materials.

The foregoing patents reflect the current state of the art of which thepresent inventor is aware. Reference to, and discussion of, thesepatents is intended to aid in discharging Applicant's acknowledged dutyof candor in disclosing information that may be relevant to theexamination of claims to the present invention. However, it isrespectfully submitted that none of the above-indicated patentsdisclose, teach, suggest, show, or otherwise render obvious, eithersingly or when considered in combination, the invention described andclaimed herein.

BRIEF SUMMARY OF THE INVENTION

The present invention provides an improved fastener apparatus for use inroofing and steel building construction. The inventive fastener includesa frusto-hemispherical head portion having a flat top surface, a curvedouter surface, a base portion, and a peripheral edge, with the flat topsurface bearing a tool fitting. A downwardly-depending lip portionextends from the head portion peripheral edge and defines an annularrecess in the base portion, the annular recess having a flat uppersurface. The lip portion has a curved outer edge, a curved lower edge,and an inner edge having a curved lower portion and a vertical upperportion terminating in the annular recess flat upper surface. A shankportion is connected to the base portion, the shank portion bearingscrew threads and a tip portion in the traditional manner. An annulargasket portion is carried on the shank portion, the gasket portionhaving a first uncompressed position contained radially within theannular recess, and a second compressed position extending radiallybeyond the lip portion outer edge. As the fastener is installed in aworkpiece, the gasket expands to contact the lip portion inner edge andextend beneath the curved lower edge to form a seal between the fastenerhead portion and the workpiece. The inventive fastener apparatuspreferably includes locking teeth terminating in the head base portion,adapted to resist loosening of the fastener from the workpiece.Alternatively, the fastener shank portion may include a depth gaugeadapted to resist over tightening of the fastener to the workpiece. Thecurved outer surface of the fastener may also include asymmetric ridgesadapted to mechanically engage moving snow or ice to resist loosening ofthe fastener from the workpiece. The fastener head portion preferablyhas a width to height ratio of between 3:1 to 5:1.

The head of the inventive fastener should have a profile as low aspossible to reduce friction during snow unloading. This low profileshape should also have a smooth aerodynamic shape to reduce windbuffeting which causes panel vibration in high wind areas. The designshould have a recess under the head to hold the rubber seal. The recessshould be as wide and as deep as possible so the seal can expand duringapplication and create a barrier of rubber between the lip of the screwhead and the panel or product being fastened. This prevents the lip fromscratching the zinc coat or paint from the surface of the product below,therefore causing the protective coating to be destroyed and enablingrust. This barrier of rubber between the lip and the panel beingfastened also protect the metal fastener and the metal panel fromelectrolysis which advances the aging process of both fastener andpanel.

The lip should also have four specific features to it. The first is onthe inside of the lip, the top half of which should be a vertical wallto stop the seal from expanding wider and cause it to expand downwardagainst the surface below, but the bottom edge should be rounded toallow the rubber seal to squeeze out from beneath the screw and not becut or pinched. The second is the bottom edge of the lip, which shouldnot be flat which would create a sharp edge and then could easilyscratch protective coatings, but should be rounded to reduce thepossibility of scratching the coatings and also to not cut or pinch therubber seal that is supposed to be escaping the recess. The third is theoutside edge of the lip, which should also be rounded so as to not cutthe rubber seal that is escaping from the recess, and not to scratch thepainted surface should the seal be pinched anyway, but also and foremostfor the reason that if the fastener is installed at an angle the outerrim will be the first to make contact and a rounded edge will do lessdamage to the protective paint or coating on the panel being fastened.

The fastener may also have a locking teeth design that should besharpened opposite the direction of application, which allows thefastener to be applied and the teeth to slide in easily without removingany metal. This sharpened angle will expand the rubber seal withoutdamaging it during application. The teeth should extend below the headline to ensure contact with the panel or product being fastened and lockitself down should forces attempt to unscrew the fastener. Next, thethickness and the width of the rubber seal should be in the proper ratioto the depth and width of the recess in the head, working in unison withthe locking teeth.

All of these features act together as a depth gauge to stop the rim ofthe screw from making contact with the panel being fastened below.First, the thick and wide rubber seal make contact which informs theoperator that the head is nearly installed, and for installation to slowdown or stop. Second, the locking teeth make contact with the raisedcone-shaped deformity in the panel (which is caused by the screw threadspenetrating the metal panel) and the teeth dramatically increaseresistance and slow the installation. The second dramatic slow downinforms the installer that the locking teeth have made contact with themetal panel and the installation is complete. The locking teethpreferably begin below the headline at the threads to ensure contact,but the teeth begin at a near vertical angle and curve wider as theyapproach the head. This curved V-shave versus a sharp straight lineV-shape allows the teeth to slide into the rubber seal and metal panelto spread the seal without damaging it, and to make contact with themetal panel and not remove any metal which will serve as a surface forthe locking teeth to bite into.

It is therefore an object of the present invention to provide a new andimproved fastener that can withstand the elements.

It is another object of the present invention to provide a new andimproved fastener that provides a high pressure water seal.

A further object or feature of the present invention is a new andimproved fastener that will not scratch the protective coating on metalpanels.

An even further object of the present invention is to provide a novelfastener that will not cause electrolysis between the screw head andmetal panel.

Other novel features which are characteristic of the invention, as toorganization and method of operation, together with further objects andadvantages thereof will be better understood from the followingdescription considered in connection with the accompanying drawing, inwhich preferred embodiments of the invention are illustrated by way ofexample. It is to be expressly understood, however, that the drawing isfor illustration and description only and is not intended as adefinition of the limits of the invention. The various features ofnovelty which characterize the invention are pointed out withparticularity in the claims annexed to and forming part of thisdisclosure. The invention resides not in any one of these features takenalone, but rather in the particular combination of all of its structuresfor the functions specified.

There has thus been broadly outlined the more important features of theinvention in order that the detailed description thereof that followsmay be better understood, and in order that the present contribution tothe art may be better appreciated. There are, of course, additionalfeatures of the invention that will be described hereinafter and whichwill form additional subject matter of the claims appended hereto. Thoseskilled in the art will appreciate that the conception upon which thisdisclosure is based readily may be utilized as a basis for the designingof other structures, methods and systems for carrying out the severalpurposes of the present invention. It is important, therefore, that theclaims be regarded as including such equivalent constructions insofar asthey do not depart from the spirit and scope of the present invention.

Further, the purpose of the Abstract is to enable the U.S. Patent andTrademark Office and the public generally, and especially thescientists, engineers and practitioners in the art who are not familiarwith patent or legal terms or phraseology, to determine quickly from acursory inspection the nature and essence of the technical disclosure ofthe application. The Abstract is neither intended to define theinvention of this application, which is measured by the claims, nor isit intended to be limiting as to the scope of the invention in any way.

Certain terminology and derivations thereof may be used in the followingdescription for convenience in reference only, and will not be limiting.For example, words such as “upward,” “downward,” “left,” and “right”would refer to directions in the drawings to which reference is madeunless otherwise stated. Similarly, words such as “inward” and “outward”would refer to directions toward and away from, respectively, thegeometric center of a device or area and designated parts thereof.References in the singular tense include the plural, and vice versa,unless otherwise noted.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The invention will be better understood and objects other than those setforth above will become apparent when consideration is given to thefollowing detailed description thereof. Such description makes referenceto the annexed drawings wherein:

FIG. 1A is a side elevation view in partial cross-section of a lockingteeth embodiment of a fastener apparatus of this invention duringinstallation;

FIG. 1B is a side elevation view in partial cross-section of thefastener apparatus of FIG. 1A as installed;

FIG. 1C is a bottom end view of the fastener apparatus of FIG. 1A;

FIG. 2A is a side elevation view in partial cross-section of analternate (no locking teeth) embodiment of a fastener apparatus of thisinvention during installation;

FIG. 2B is a side elevation view in partial cross-section of thefastener apparatus of FIG. 2B as installed;

FIG. 3A is a side elevation view of a self-tightening head embodiment ofa fastener apparatus of this invention;

FIG. 3B is a top plan view of the fastener apparatus of FIG. 3A asinstalled;

FIG. 4A is a side elevation view in partial cross-section of a flat headembodiment of a fastener apparatus of this invention duringinstallation;

FIG. 4B is a side elevation view of the fastener apparatus of FIG. 4A asinstalled; and

FIG. 5 is a side elevation view in partial cross-section of a nail headand elongated threaded shank embodiment of a fastener apparatus of thisinvention during installation.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1 through 5, wherein like reference numerals refer tolike components in the various views, there is illustrated therein a newand improved fastener apparatus, generally denominated 10 herein.

FIG. 1A is a side elevation view in partial cross-section of a lockingteeth embodiment of a fastener apparatus 10 of this invention duringinstallation, while FIG. 1B is a side elevation view and FIG. 1C is abottom end view. The inventive fastener 10 includes afrusto-hemispherical head portion 12 having a flat top surface 14, acurved outer surface 16, a base portion 18, and a peripheral edge 20,with the flat top surface bearing a tool fitting 22. Adownwardly-depending lip portion 24 extends from the head portionperipheral edge 20 and defines an annular recess 26 in the base portion18. The annular recess 26 has a flat upper surface 28. The lip portion24 has a curved outer edge 30, a curved lower edge 32, and an inner edge34 having a curved lower portion 36 and a vertical upper portion 38terminating in the annular recess flat upper surface 28. A shank portion40 is connected to the base portion 18, the shank portion bearing screwthreads 42 and a tip portion 44 as is well known in the art.

An annular gasket portion 50 is carried on the shank portion, the gasketportion having a first uncompressed position contained radially withinthe annular recess (e.g., FIG. 1A), and a second compressed positionextending radially beyond the lip portion outer edge (FIG. 1B). As thefastener is installed in a workpiece, the gasket 50 expands to contactthe lip portion inner edge 34 and extend beneath the curved lower edge32 to form a seal between the fastener head portion and the workpiece W.

The flat top 14 is designed to reduce the low profile of the head asmuch as possible and still allow enough material in the head toaccommodate an inset tool fitting 22. The wider or larger a tool fittingthat is used in the fastener head the wider the flat spot should be. Abalance between the tool fitting size and the shank size should beadhered to so as to not weaken the head strength by using too large atool fitting or by using too deep a tool fitting. The flat top is“pre-formed” into the head so that whatever type of tool fitting is usedthe tool fitting is accurately punched into the head without flaws ordefects. This will also reduce the cost and necessity for retooling bynot punching into a rounded head that would wear out tool fittings muchfaster.

The flat spot reduces friction between the head and snow, ice, pineneedles, leaves, branches, etc. from having anything on the fastener tobuild up on. Snow and ice that naturally occurs builds up and thenunloads over the screw heads is a damaging element to any fastener. Theact of thousands of pounds of snow and ice unloading, rips and cuts it'sway over the existing fasteners and actually unscrews them and/or tearsthem completely out. The flat spot is also intended and designed toreduce wind buffeting that will cause building and panel vibration,which will weaken fasteners contact and wear out the seal over time.

The rounded or convex outer head surface 16 is designed in a shallowrounded manner to give a smooth surface and a low profile “ramp” to theleading edge of the fastener head. This allows snow and ice, branches,pine needles, etc. to ramp or jump over the head, and reduces the impactor friction caused when snow and ice are naturally unloading from theroof.

The recess 26 is designed very wide and as deep as possible toaccommodate a large (and therefore strong) rubber seal 50. The seal isto be trapped and protected under the head of the fastener but therecess is also designed to allow a small amount of the rubber seal toescape and create a barrier of rubber between the outer rim of therecess and the metal panel being fastened. The desired effect of using alarge strong seal is to have a seal that can withstand the pressure ofthe head tightening around it and the seal will not fail before the ribof the panel bends below it. The ribs of a metal roof will dent at acertain pressure and the installer should stop applying pressure to thescrew before this happens. In other words there is a limit to how muchpressure can be applied to the panel, therefore a balance or ratio ofrubber seal thickness and width must be obtained for the fasteners headto seat down properly without causing too much pressure and bending ofthe roofing panel being fastened.

A further desired effect is to create three seals out of one seal. Thefirst seal 50 a is the rubber that escapes from the recess. Water, UVand the elements attack this area of the seal first. The second seal 50b is the barrier of rubber seal pinched between the bottom edge 32 ofthe lip 24 and the panel being fastened. The third seal 50 c is therubber seal that is entirely trapped and protected within the recess 26.Thus the inventive fastener provides three areas of sealing to stopwater from leaking, rusting from scratching and electrolysis between thetwo metals.

The vertical upper portion 38 of the lip 24 should be vertical or asteep annular shape to give the top edge of the rubber grommet 50 aplace to seat itself and stop the seal from expanding laterally and tostart the seal expanding downward. The annular shape should be as steeptowards vertical as possible or vertical so as to not allow the rubberseals top edge to escape from the recess, before the head has had achance to seat down enough to trap the seal. The top half is vertical orsteep annular and smoothly flows into the lower half 36 that is roundedand allows the lower half of the rubber grommet 50 to escape from therecess 26.

The outside edge 30 of the lip portion 24 should be rounded. The rubberseal 50 is intended to squeeze out under the extreme high pressure therecess applies to the rubber seal upon final tightening. The roundedoutside edge 30 of the lip will not pinch or cut the rubber seal that isallowed to escape from the recess.

The outside edge 30 is also rounded to reduce the chances of the outeredge of the fastener scratching the painted or otherwise protectivecoated panel being fastened. A fastener installed incorrectly at aslight angle may allow for the rim of the fastener to make contact withthe painted or protected panel and scratch it. A rounded edge is lesslikely to scratch deep enough to cause rusting and premature aging.

The bottom edge 32 of the lip portion 24 should also be rounded toprevent pinching of the rubber seal as it expands radially outward. Thebottom edge 32 is also designed in this rounded manner to reduce thechances of the outer edge of the fastener scratching the painted orotherwise protective coated panel being fastened.

The curved lower portion 36 of the lip portion 24 should be rounded toallow for a small amount of the rubber seal 50 to escape without beingcut into by a sharp edge at the inside bottom edge of the lip. A lipwith a sharpened edge in this location would allow that sharp edge tocut into the rubber seal and cause damage that may result in completeseal failure. This design allows for a small amount of seal to escapebut the majority of the seal be trapped, all during a very quick motionat the last second as the fastener head reaches the bottom and tightensdown, but not to pinch to hard and damage the seal under the outer rimin the process. Simply put rubber can form to a rounded shape betterthen to a sharp edge without damaging the rubber.

The overall total width of the lip portion is important in the designand should be located at the extreme outer edge of the fastener headsunderside. The lip should be as thin as possible (widthwise) to allowfor a very wide rubber seal or grommet to be wide enough to be near theedge of the fastener. The purpose is to fill the entire void of therecess and allow for the excess rubber seal to escape and create arubber barrier between the metal fastener head and the metal panel beingfastened. However, the lip should also have a minimum width to it so asto not create a sharp edge. The width and roundness of the lip shouldaccommodate the flexing characteristics of the rubber seal or grommetused.

FIGS. 1A-1C also illustrate locking teeth 60 adapted to resist looseningof the fastener from the workpiece. The vertical wall side 62 of thelocking teeth must be the trailing edge side as the fastener is appliedand the leading edge side as the fastener is unscrewed. The purpose forthis design feature is for the vertical wall to be sharp when unscrewingbut not sharp while fastening or applying. The leading edge whileapplying a fastener would become the trailing edge when unscrewing thefastener. Sloping wall side 64 is a long and gradual slope down from thetop or sharp point of one high vertical wall 62 to the low point at thenext vertical wall in the next locking tooth. Together these featurescreate teeth that are sharpened in a direction opposite to the directionof tightening a fastener.

This design allows for the teeth to slide in during application and notdamage the rubber seal. The teeth will slide past the rubber sealwithout cutting or tearing the seal, which might cause damage. Thisdesign also allows the teeth to penetrate the metal panel being fastenedwithout removing any metal that will in turn become a place for theteeth to bite into and stop the fastener from unscrewing.

The anti-back-out teeth also provide more mass for a larger connectionfrom the shank or threaded portion of the fastener to the head or top ofthe fastener. This makes the head connection stronger and increases thescrews resistance to head shear. Head shear can occur when snow and icetear at the screw head and or when the roofing panel itself is pulledparallel to the roofing substructure causing a scissor like effect onthe fastener.

The width of the anti-back-out teeth creates a stronger head connection,which allows for a deeper tool fitting. Theoretically a tool fitting canbe cut through the head of the fastener directly into the vicinity ofthe shank and locking teeth. The shank would have to be large enough sothe teeth could retain the same strength as a shank of the samedimensions. Also the tool fitting could not penetrate too far into theshank as to weaken it below standards.

The curved flare shape 66 of the teeth should begin at the shank 40 at anear vertical angle and curve outward as the teeth near the underside ofthe head 12. At the head the teeth angle should be nearly horizontal.This curve further helps the locking teeth to slide inward into therubber seal while expanding it without damaging it. The curved flareshape of the teeth helps to ensure that material from the panel, whichis to serve as a place for the teeth to bite into, will not be removedduring installation of the fastener.

The curved flare shape of the teeth also helps to stop the raised metalprotrusion (caused during the threads penetration of the panel) fromdamaging the rubber seal at the end of installation. When a fastenerpenetrates a metal panel a small raised protrusion of metal rises up onone side of the threads. The bottoms of the inventive teeth are nearvertical and protrude below the bottom line of the head so they ensurecontact with the metal panel, but at the midpoint the teeth are flaringat roughly a 45-degree angle, which stops the metal protrusion fromriding up into the recess any farther and causing damage to the rubberseal.

The depth of the teeth should extend below the headline or the verylowest point of the head. This is to ensure contact between the lockingteeth and the panel being fastened. The curved flare and depth of thelocking teeth work together to force their way into a metal panel andcause the panel to stretch around and form to the teeth, ensuring a goodlock.

There is a certain ratio that should be achieved between the width anddepth of the purposely-wide recess and the width and thickness of therubber seal or grommet. The desired effect is to have a wide enoughrecess and a wide enough seal, to have it near the edge of the screwhead as possible before tightening causes the seal to expand underpressure. This means that when the rubber seal expands, a small amount(e.g., 0.05% to 5%) of the rubber seal will escape from the recess. Theseal that escapes creates two separate features: a barrier of rubberbetween the bottom of the lip rim and the panel being fastened issqueezed out from the recess. This stops the lip of the fastener headfrom scratching the painted surface of the panel being fastened. Also, afirst seal is created outside the recess and around the perimeter of thefastener head.

This first seal area is created outside the recess and around theperimeter of the fastener head when the fastener is tightened down.Because the fastener design incorporates rounded edges on the lip, theexcess rubber seal that is allowed to squeeze out creates a seal outsideof the recess. However, this “exposed” seal is more vulnerable to theelements and will be destroyed faster than the protected seal. For thisreason it is preferable to keep a proper ratio of rubber to recess so asto limit the rubber that escapes from the recess to just under the lip.It is desirable for some of the seal to escape to the lip and past, butpast only due to manufacturing flaws. It is preferable to minimize thisfeature as much as possible to keep the rubber seal from escaping intothe direct elements. There is an advantage to having exposed rubberoutside of the recess, in that it will be the first attacked by theelements before the rubber inside the recess ever even begins to wear,which may extend the life of the rubber seal. The fluctuations inmanufacturing will allow some fasteners seals to escape more thanothers.

The excess rubber seal that purposely squeezes out from the recess andcreates the rubber barrier of seal under the bottom edge of the lip alsobecomes a more dense and compacted seal than the exposed seal, but onlyafter the outer exposed seal has worn away. This area becomes the secondline of defense, as it will wear out before the rubber seal that isfully trapped and protected in the recess. The outer rubber seal maybreak free from the screw head after years of UV and the elements dryingout the excess seal.

The seal that is fully trapped inside the recess is the third defenseagainst water and leakage. The three separate locations the head pressesdown on the seal create three separate densities of the rubber. Thefirst line of defense is the seal that has escaped from the recess andis directly exposed to the elements. This seal is free to expand back toits regular density and stops the elements from attacking the innerseal. It is the first line of defense. The second line of defense is thebarrier of rubber seal located under the lip of the screw head. Thisseal has been pressed down by the head to an extremely dense but thinlayer of material. The third line of defense is the rubber seal that isfully trapped under the head inside the recess. This layer will not beattacked by the elements until the entire first and second lines ofdefense have completely worn away. This protected seal has been packedto the optimum density.

Within the recess the rubber seal has been quickly trapped at the end ofthe installation. A very large rubber seal has been compacted into asmall void (the recess) and has been compacted into a high pressureseal. That seal will be able to hold extreme amounts of pressure incomparison to the original hex heads, which do not trap the seal in arecess and are very limited as to how much pressure, can be applied tothe seal before failure of the seal occurs. The inventive recess designutilizing rounded edges and a wide recess, plus the large rubber sealsize to large recess size ratio ensures that a standard rubber seal canbe compacted into a high-pressure seal. The shape of the lockinganti-back-out teeth ensures that the seal will not be damaged inside therecess.

The threads at the top of the shank are designed to have the extremelast thread 42 a at the very top to cut into one side of theanti-back-out locking teeth. The reason for this design feature is toguide the raised metal protrusion in the panel being fastened to ride uponto the locking teeth and ensure contact between the teeth and thepanel being fastened.

This thread cut on the shank rising into the locking teeth, also worksas a contact limiter because the cut ends equal to the bottom of theheadline (the lowest point of the head). Where the thread cut ends willlimit how high the panel being fastened will rise into the recess 60.The reason is the shape; flare and curvature of the locking teeth are atsuch an angle at the headline as to reverse the panel protrusion fromrising and it is pushed back down by the ever-flattening angle of thelocking teeth.

This universal head and locking device combination can be made toaccommodate any type of shank design from a bolt to a screw to a rivet.This design can be made in any scale to accommodate any type of useincluding boats, trailers, motor homes, trailer homes, RV's, raingutters and downspouts, airplanes, and all types of metal-to-metal ormetal-to-wood contacts.

This design can also be used on roofing flashing including heat vents,eyebrow vents, perimeter and parapet wall caps, metal nosing of alltypes, and can be used directly on composition roofing in areas where anail and liquid tar are now acceptable.

FIG. 2A is a side elevation view in partial cross-section of analternate (no locking teeth) embodiment 100 of a fastener apparatus ofthis invention during installation, while FIG. 2B is a side elevationview in partial cross-section of the fastener 100 as installed. On thisdesign, the shank threads 102 stop below the headline 104 so as to stopthe raised metal panel protrusion from riding into the recess 106 anddamaging the seal 108. This is a depth gauge 110 which stops the lip 112from making contact. This upper shank area is also not threaded so thehead to shank connection is larger and stronger so as to support thewide head design without the head easily shearing off.

FIG. 3A is a side elevation view of a self-tightening head embodiment200 of a fastener apparatus of this invention, while FIG. 3B is a topplan view of the fastener 200 as installed. The head of this particulardesign works with the snow and ice that is unloading off a rooftop andsliding over the fastener head. The intent is to have a series of raisedvertical walls 202 that are sharp at the top 204 and with a backside 206that slopes down from the top of one vertical wall to the bottom of thenext vertical wall. The overall shape is somewhat similar to that of apropeller. The concept has the vertical wall side catching the snow andice sliding which will apply a turning force in the direction oftightening the fastener. This wall must be limited to prevent snow andice from over tightening and stripping the fasteners teeth from thesubstructure.

The backside in this design is sloped from the top of one vertical catchwall, around the head and down to the bottom of the next vertical wall.The intent is to have this fastener work similar to a security fastenerthat can only be tightened and not loosened, not loosened because thereis no catch for a tool to grab onto and loosen it (the sloped side). Thesloped backside is always on the opposite side as the catch side due tothe propeller shape. This means that the side that would normally havean equal friction to the catch side, forms a ramp and has much lessfriction applied to the direction, which would unscrew a fastener. Allof the actions set forth in this design require snow and ice to slideover the head for it to work.

FIG. 4A is a side elevation view in partial cross-section of a flat headembodiment 300 of a fastener apparatus of this invention duringinstallation, while FIG. 4B is a side elevation view of the fastener 300as installed. This design works exactly as do the previous embodimentswith one exception, the extreme flat top of the head design. This designenhances all of the low profile features described above.

The outer edge 302 of the top of the fastener head 304 may be rounded asshown or it can be designed to incorporate an annular shape to allow aramp at the first impact point at the edge of the fastener head. Thisramp would push the fasteners head down as the snow and ice are pushedupward and over the fastener head. This is similar to the other designswhich also intend to create a ramp that pushes the leading edge of thefastener downward, instead of pulling it up and out or sideways if thesnow and ice could get under the front of the head. The lack of thisramp on the hex head screw is what causes those fasteners to be pulledout as they are.

To make this fastener design work properly, an increased shank 306 sizeand properly scaled up anti back-out teeth 308 should be added. Theshank and locking teeth should be increased in size to accommodate atool fitting 310 being punched through the head and into the lockingteeth and wider shank. The extreme low profile created may not affordenough depth to accommodate a tool fitting unless the fitting goesthrough the head and into the shank area. In order to re-strengthen thehead back to ANSI Standards, a wider shank should be used. In otherwords, if to fasten a roof to building code, a #9 size shank wererequired, then with this particular fastener design one would preferablyuse a #10 size shank in order to have an equally strong fastener.

FIG. 5 is a side elevation view in partial cross-section of a nail headand elongated thread shank embodiment 400 of a fastener apparatus ofthis invention during installation. This is a nail design that utilizesmany of the features described above. The differences are a nail head402 which does not require a tool fitting to be punched into it,therefore a standard shank size will remain at its intended strength.

Elongated threads 404 impart a twisting motion during application thatwill allow the locking teeth 406 to work similarly to how they work whenusing a shank with screw threads. The fastener spins as it is appliedand locks into place when it tries to unscrew, or in the case of thenail, twist out.

In order for the head of the inventive fastener designs to remain strongenough to equal ANSI Standards and pass all required UL Testing for usein the field, while incorporating the deep recess and the inset toolfitting which combined will weaken the head, a ratio between the widthof the head and the height of the head should be maintained.

The low profile width to height ratio in this invention is preferablywithin a range of a minimum 3 parts in width to 1 part in height (i.e.,three times wider then it is tall) or 3 to 1, to a maximum of 5 parts inwidth to 1 part in height (five times wider then it is tall) or 5 to 1.

The most optimal ratios for the fasteners in the fields of metal roofingand/or pre-fabricated steel buildings are 3.5 or 4 to 1. It is desirableto resolve maximum width and required strength issues to meet buildingcodes and also remain within the width of the rib on the manufacturerspanel design, while maintaining the desired low profile.

The minimum of 3 to 1 should be maintained because if the ratio is anysmaller (such as 2 to 1) the low profile aspect will be lost resultingin a simple rounded top.

The maximum ratio of 5 to 1 should be maintained so that the toolfitting can be punched into the head without weakening the head andmaking it vulnerable to head shear. The wider the fastener head is, themore leverage the outer edge of the fastener head has to bend and/orbreak the head from the shank. A minimum depth for a tool fitting isrequired for installing the fastener; and this tool depth determines theoverall width of the fastener when maintaining the ratios. Whenoperating in the fields of metal roofing and steel buildings the averagewidth of the ribs are roughly ⅝ inch, accordingly, the fastener forthese industries has a rough width of 5.45 thousands of an inch andtherefore would be automatically a height of roughly 1.5 thousands of aninch.

Any larger ratio such as a 6 to 1 or even a 10 to 1 would lead the lowprofile into a flat top fastener design. In these separate designs thetool fitting must be punched through the head and into the shank of thefastener. There are two ways to solve this: to increase the shankdiameter to accommodate the tool, but remain at a lower ANSI Standardfor the strength (e.g., a 10 shank would have the strength of an 8shank); or to incorporate the locking teeth design that returns thestrength to the head by adding more steel for the head to shankconnection.

There is no one set size for the inventive fastener. The size of thehead is determined by the required shank size for a particular project.For example, some steel buildings utilize very large roofing panels andwall panels, which have a wider rib and also require a stronger fastenerto meet the building code.

Variable ratios may be used in creating separate fasteners for separateindustries or for individual fields of use, to increase or decrease thetool fitting depth and achieve ANSI Standards and therefore maintain theproper torque values and head strengths for the industry in which thefastener will be used.

The flat spot on the top of the fastener is a further variable in thedesign ratio. In order to make sure a proper tool depth is achieved toproperly install the fastener, but also to achieve the perfect heightand keep a low profile, the flat spot is the determining height. Oncethe tool depth is determined the top of the fastener height isdetermined prior to the tool being punched.

The inventive fastener may be installed in the pan of the building paneland not on top of the rib as it is currently installed. The pan is theextreme bottom wide spot in between the raised ribs of the steel panel.The old style fasteners are normally installed on the top of the rib soas to prepare for the expected failure of the product and when it doesfail the rainwater runoff drains down in the pan and not on top of therib.

The above disclosure is sufficient to enable one of ordinary skill inthe art to practice the invention, and provides the best mode ofpracticing the invention presently contemplated by the inventor. Whilethere is provided herein a full and complete disclosure of the preferredembodiments of this invention, it is not desired to limit the inventionto the exact construction, dimensional relationships, and operationshown and described. Various modifications, alternative constructions,changes and equivalents will readily occur to those skilled in the artand may be employed, as suitable, without departing from the true spiritand scope of the invention. Such changes might involve alternativematerials, components, structural arrangements, sizes, shapes, forms,functions, operational features or the like.

Therefore, the above description and illustrations should not beconstrued as limiting the scope of the invention, which is defined bythe appended claims.

1. A fastener apparatus for securing a workpiece, said fastenerapparatus comprising a frusto-hemispherical head and shank appendedthereto, said frusto-hemispherical having a body comprising asubstantially extended flat top surface a curved outer surface and aperipheral edge, which incorporates a seal seating zone, said headfurther having a downwardly-appending lip portion extending from saidcurved outer surface and defining an annular recess within said bodycreating a leading edge as a shallow ramp for changing sideways andshearing energy of snow and ice into a downward force energy as it ridesup said ramp causing snow to ride over and split around the sides ofsaid head, said annular recess having a substantially flat upper surfaceand substantially vertical sidewalls transitioning from saidsubstantially flat upper surface to said downwardly-appending lipportion, said lip portion having a curved outer edge creating the sealseating zone and a curved lower edge, a series of locking teeth adaptedto resist loosening of said fastener from said workpiece, each of saidlocking teeth having a first end being substantially vertical at saidshank and gradually curving to being substantially horizontal withinsaid annular recess at their second end and a midpoint wherein saidlocking teeth are flared at an approximately 45-degree angle to saidfirst and second ends which is equal to the lowest portion of the outerrim, said shank having a series of threads for engaging said workpieceand drawing said frusto-hemispherical head thereto, said threadsextending along said shank toward said head such that a last threadproximate said frusto-hemispherical head cuts into one side of saidlooking teeth and an annular gasket located within said annular recess,said recess and gasket being sized such that when said fastenerapparatus is fully secured to said workpiece, a first portion of saidgasket protrudes from said frusto-hemispherical head to provide a firstseal, a second portion of said gasket resides and is compressed betweenand surrounding said curved lower edge of said lip and said workpiece toprovide a second seal and a third portion of said gasket remains withinsaid annular recess to provide a third seal.
 2. The fastener apparatusof claim 1 wherein said substantially extended flat-top surface isprovided with a tool fitting and is formed to provide a stable flat andwide platform for installation with a matching shaped tool driver. 3.The fastener apparatus of claim 1 wherein said locking teeth have frontsides and back sides, said locking teeth front sides have verticalwalls, said vertical walls are trailing edges thereof as said fastenerapparatus is applied to said workpiece and the leading edges thereof assaid fastener apparatus is removed from said workpiece, and said lockingteeth back sides have angled walls, said angled walls prevent workpiecemetal from being honed or stripped when the fastener apparatus isinstalled in the workpiece.
 4. The fastener apparatus of claim 3 whereinsaid locking teeth are characterized as having sharpened edges in thedirection opposite to the direction in which the fastener apparatus istightened to said workpiece.
 5. The fastener apparatus of claim 1wherein said annular teeth are sized and positioned such that theyprovide additional mass between said shank and frusto-hemispherical headto substantially increase resistance to head shear, which is requireddue to the low profile head being thin and the depth of the tool fittingremoved having weakened the head to shank connection.
 6. The fastenerapparatus of claim 1 wherein said looking teeth extend below saidfrusto-hemispherical head to insure engagement with said workpiece uponapplication of said fastener apparatus with said workpiece.
 7. Thefastener apparatus of claim 1 wherein approximately 0.5 to 5 percent ofsaid annular gasket comprises said first seal.
 8. The fastener apparatusof claim 1 wherein said frusto-hemispherical head has a width and aheight, the ratio of said width and height being approximately 3:1 to5:1.
 9. The fastener apparatus of claim 1 wherein said second portion ofsaid gasket substantially prevents water from penetrating under saidfrusto-hemispherical head and acts as a scratch barrier between suchhead and workpiece further acting as a depth gauge working in unisonwith locking teeth and creating under said locking teeth a seal bymerging with the threads of said teeth.
 10. The fastener apparatus ofclaim 1 wherein the depth of said locking teeth is limited to thethickness of panels constituting said workpiece to be fastened.
 11. Thefastener apparatus of claim 1 wherein threads of said shank are cutdirectly into said locking teeth in order to ensure contact is madebetween said locking teeth and panel being fastened and to ensure thatno blank thread-less zone exists where spinout of said fastenerapparatus can occur.
 12. The fastener apparatus of claim 1 wherein thefinal thread of said shank cuts into said locking teeth to act as acontact limiter.
 13. The fastener apparatus of claim 1 wherein aheadline exists for sealing and protecting said exposed gasket, saidheadline being located on the outermost point of saidfrusto-hemispherical head and around its circumference and is locatedabove the lowest portion of the lip.
 14. The fastener apparatus of claim13 wherein a said seating transition prevents said exposed gasket frombeing cut.
 15. The fastener apparatus of claim 1 wherein said workpieceis deformed around said locking teeth upon engagement of said fastenerapparatus to said workpiece, the locking teeth provide an anti-backoutfunction.
 16. The fastener apparatus of claim 15 wherein said finalthread channel is sized and positioned to cut a guide to form saidworkpiece and to guide the workpiece over said locking teeth.
 17. Thefastener apparatus of claim 1 wherein said frusto-hemispherical head isprovided with extended flat top surface which is as wide as possible andis preformed to accept a tool fitting into a flat surface rather than around surface for accuracy which will provide reducing tool costs and toprovide enhanced unloading of snow and ice making contact with saidfrusto-hemispherical head.
 18. The fastener apparatus of claim 1 whereina measurement taken from the bottom of the ceiling portion at the bottomof said locking teeth to the top of said frusto-hemispherical headcharacterized as having a height to width ratio of from approximately3:1 to 5:1.
 19. A fastener apparatus for securing a workpiece, saidfastener apparatus comprising a frusto-hemispherical head and shankappended thereto, said frusto-hemispherical head having a bodycomprising a substantially extended flat top surface a curved outersurface and a peripheral edge, said head further having adownwardly-appending lip portion extending from said curved outersurface and defining an angular recess within said body, said annularrecess having a substantially flat upper surface and substantiallyvertical sidewalls transitioning from said substantially flat uppersurface to said downwardly-appending lip portion, creating a leadingedge as a shallow ramp for changing sideways and shearing energy of snowand ice into a downward force energy as it rides up said ramp causingsnow to ride over and split around the sides of said head, said lipportion having a curved outer edge a curved lower edge and an annulargasket located within said annular recess, said recess and gasket beingsized such that when said fastener apparatus is fully secured to saidworkpiece, a first portion of said gasket protrudes from saidfrusto-hemispherical head into the seal seating area to provide a firsthigh pressure seal, a second portion of said gasket resides and iscompressed between said curved lower edge of said lip and said workpieceto provide a second seal and a third portion of said gasket remainswithin said annular recess to provide a third seal.
 20. The fastenerapparatus of claim 19 wherein the third portion of said gasket is fullyprotected from ultraviolet radiation and represents the majority of thesealing function while said first seal acts as a depth gauge as itbegins to compress under said frusto-hemispherical head.
 21. Thefastener apparatus of claim 19 wherein said first portion of said gasketacts as a first line of defense working in unison to extend the life ofsaid gasket by allowing the gasket to deteriorate progressively fromeach line of defense to the next and by further providing a scratchbarrier and creating a depth gauge from said gasket upon applying saidfastener apparatus to said workpiece and further acting as a visualdepth gauge as rubber escapes from said annular recess into plain viewallowing an installer to visually confirm that said fastener apparatushas been installed.
 22. The fastener apparatus of claim 19 wherein saidgasket, in its uncompressed state, occupies approximately 85-95 percentof the width of said annular recess but does not fully fill said annularrecess until said gasket is compressed by applying said fastenerapparatus to said workpiece until compressed to expand to fully fill thewidth of said annular recess where it stops expanding radially withinthe annular recess by hitting the recess walls whereupon the bottomportion of the gasket squeezes from the bottommost portion of the recessunder said lip portion to create said first seal, second seal and thirdseal, creating an overall high pressure seal, with three lines ofdefense.
 23. The fastener apparatus of claim 19 wherein 0.5-5.0 percentof said gasket comprises first seal extending from saidfrusto-hemispherical head upon application of said fastener apparatus tosaid workpiece and wherein the ratio of gasket seal to annular recessheight is approximately from 1.75:1 to 2.3:1.